Have a question or comment for Jon? Email him at jon_wertheim@yahoo.com or tweet him @jon_wertheim.

Right to the questions:

Jon, with the issue of medical exemptions for banned drugs in the news due to the email hack, can you explain the rationale for allowing an athlete who receives a valid exemption to compete? Granted, the athlete has done nothing wrong, but even if a banned drug is being taken for a legitimate medical purpose, the bottom line is that the athlete's performance is being enhanced—even if the enhancement is incidental. This gives the athlete who is taking the drug an unfair advantage. How then is the exemption justified?—Sigmond, St. Louis

• The issue of therapeutic use exemptions were a hot topic this week, triggered by both the Fancy Bear hack and then this disturbing Ben Rothenberg piece of enterprise on an American player and her TUE.

First, to Sigmond’s question, the idea is the athletes have a pre-existing condition that require a banned substance—or, more often, a medication that contains vestiges of a banned substance—to treat. As such, they seek an exemption for that substance. The rationale: performance is not being enhanced by substance X. It is simply that substance X is being used to remedy a problem and enable the athlete to achieve a baseline level. (This is akin to getting Lasek to correct bad eyesight and attain 20/20 vision, not 20/10 vision.) Without TUEs, it would seem unfair that, asthmatics, for instance, might never be able to compete.

In some cases, the exemption is clearly legitimate and the TUE request is granted. In other cases, it is not. I know of an athlete who claimed that he was prone to jetlag and requested an exemption for jetlag medication containing methylhexaneamine, which is banned. That was rejected. Another athlete sought an exemption for a banned substance in his hair loss medication. (Presumably, the beta blocker, monoxidil.) That request, too, was banned.

Still, there is—was, the optimists might contend—gaping potential for loopholes. I first learned about the prevalence of TUE’s when I was writing a book on mixed martial arts in 2008 or so. It was an open secret among fighters that they could simply find some hack doctor to say they suffered from a deficiency—low testosterone, was plaguing these fighters with, ahem, alarming frequency—and required a TUE to correct. The state athletic commission (often understaffed, underinformed and fearful of litigation) would rubber-stamp the TUE. And when the fighter tested positive for, say, synthetic testosterone, they would brandish the TUE and all was forgiven.

Eventually authorities got hip to this ruse and, well, draw your own conclusions. (Keep in mind, too: steroids are known to induce a deficiency in testosterone, i.e. hypogonadism. An obvious question: even if you can demonstrate low testosterone, should it receive a TUE when it could likely have been caused by previous steroid use?)

Anyway, it stands to reason that in some of the cases that came to light last week, these requests were thoroughly legitimate, granted accordingly, and the athlete, doctor and federations all followed protocol. In other words, the system worked. In other cases, grey areas appear to have been breached. In some cases by an athlete. In some cases by a too-willing doctor. In some cases by a sloppy or willfully blind federation. (And sometimes all three.) No question these TUEs need to come under more scrutiny.

I do like Nadal’s comments. Though it would obviously come at a privacy cost, why not make TUEs public? After his name and TUEs were leaked—and, we should add, if you’ve been following his career, his TUEs line up perfectly with his periods of injury; to me, anyway, dousing and not arousing suspicion— Nadal said: “Sport has to take a step forward and be totally transparent. I have been saying this for years.”

There's been plenty of talk about Juan Martin's backhand struggles due to the wrist injuries. McEnroe said he thinks del Potro can't make it back to the top of the game (he said No. 6 ranking specifically) if del Potro is unable to hit his backhand rather than almost exclusively relying on the slice.

So I was wondering, has anyone asked del Potro if he's considered abandoning the two-handed backhand and trying to switch to a one-hander? And if so, what was his response? I know it's less than ideal, but seems like it could at least be worth exploring. Not sure if there have been many other players to try making that switch in the middle of their careers, but Tsonga is certainly an example of someone who has dabbled with it.—Matt Schiffman, Chicago

• Good question. I remember we raised this several years ago when Kim Clijsters had a similar injury to her “off” wrist. She’s such a good athlete and had such a good serve; why not try a one-hander?

First thought: del Potro sure seems to be doing okay with his two-hander. When you’ve beaten Wawrinka, Djokovic, Nadal and Murray in the last two months, you’re doing something right. His slice is improved and you have to think that the backhand drive is as much about confidence as it is physical limitations.

While I share your curiosity, I think it’s hard to exaggerate the difficulty of this transition. Goofing around and hitting a one-hander in practice or even during an inconsequential point is one thing. Actually making this a default shot is another matter altogether. In the course of a point, it would be hard to forsake slicing—low-risk and comfortable—over a zinging one-hander that won’t feel natural.

I recently read that Maria Sharapova did an internship with the NBA. There were photos of her with Adam Silver and other executives. It just struck me as inappropriate. Here is an athlete serving a two-year suspension for drugs and a major sports organization is engaging in a publicity stunt with the athlete. I wouldn't give it a second thought if the internship was with a company related to her other business ventures but the NBA? I always enjoy hearing what I think is very balanced insight from you.—Sharon Newell, Tucson, Ariz.

• I wouldn’t disagree with that. While the NBA has its own drug policy, it doesn’t exactly bolster WADA’s credibility when an athlete found in contravention of its anti-doping rules is then given a much-publicized (and presumably much-coveted) employment opportunity by a major sports league. This is something other than a ringing endorsement of WADA’s code, its authority and its heft.

And if I’m the NBA Players Association, I have taken note of this. The NBA has been blissfully absent from most PED-in-sports conversation. But there are some exceptions. Next time the league takes a hard-line stance on someone like Mitch McGary maybe it’s worth pointing out that this is the same league that was sufficiently unbothered by a tennis player’s positive test that it welcomed her in the workplace.

I suppose the flip side goes like this: a) Sharapova’s positive test seems to be more of an issue of sloppiness and than conventional cheating to gain a competitive advantage. Some mercy might be in order. b) Sharapova’s “internship” was administrative in nature and had nothing to do with competing. Is it exceedingly harsh to ban her from an office job that, presumably, has nothing to do with what she did or didn’t do in her capacity as an athlete?

Speaking of Sharapova, her appeal decision will be issued early next month. My strong suspicion: her suspension gets reduced to a year. What's become clear: Sharapova is guilty of sloppiness. She is guilty of bad PR advice. (Note how Varvara Lepchenko's fact pattern was remarkably similar yet she escaped sanction.) But guilty of blatantly cheating? No.

When was the last time only one of the Big 4 was in the semis of a major?—@jektweet

• This question came during the U.S. Open (when only Djokovic remained) but I like it—and it underscores the dominance of the Big Four. Answer: French Open 2010.

​You would likely NOT want to address this question, but do tennis writers or journalists ever apologize if they have written something silly or unkind or ungracious about a player who does not deserve the remarks? I am naming names here: [A writer] has consistently denigrated Kerber and social media have called him on his remarks. Since Kerber won the U.S. Open and reached No. 1, I have not read a single word of congratulation or acknowledgement.—M Ng, Vancouver, Canada

• They strip you of your media credentials if you ever even think to apologize.

Hana Mandlikova won four Grand Slams with career high ranking of No. 3. Virginia Wade won three Grand Slams with career high ranking of No. 2, but the Grand Slams predate the ranking system.—Cheers! Mike

• Thanks. Four Majors with a career-high ranking of No. 3 is a feat.

I assume the love of Gael Monfils’ life married Raleigh St. Clair yesterday?

—John Dugan Boulder, Colo. (formerly of Memphis, Tenn.)

• Well played. John Dugan sent this during the Monfils-Djokovic match. But it was so strong, we offer it again, almost two weeks later.

Shots, Miscellany

• A lot of you wrote in condemning Malek Jaziri of Tunisia when he declined to play an Israeli opponent several years ago. Let the record reflect, Jaziri not only played Dudi Sela last weekend, but beat him by the bizarre score of 6-1. 1-6. 6-0.

• Stanlislas the Manislas does Charlie Rose:

Love Wawrinka’s candor here.

Q: Can you be No. 1?

A: No. I’m not consistent enough.

• Bryan Park of Philly: Two things in your 50 parting thoughts from the U.S. Open caught my eye: Totally agree with you on the classiness of Nadal immediately following his defeat to Pouille. If so many other defeated players simply leave the court as quickly as possible, how much more so does Nadal have the right to? Yet he acknowledges the crowd and signs autographs on his way out. How jaw-droppingly classy is that? Totally agree with you on the punishing nature of five-setters in this era. I would support a move at the majors for five sets only in the second week of play. And the other majors need to catch up to the U.S. Open in instituting a tiebreaker for the final set. No one wants to see a match decided by 70-68 in the fifth set, played over three days.

Michelle rightly notes: In your Mailbag you pointed out how Vilas has never been No. 1 (like Wawrinka and Murray) despite having three or more majors. Technically that is correct but there has been controversy about it. He probably would have been a No. 1 had the rankings been published weekly like they are now.

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